diff --git a/lib/mutant/runner/subject.rb b/lib/mutant/runner/subject.rb
index 1352f522..d6e40d37 100644
--- a/lib/mutant/runner/subject.rb
+++ b/lib/mutant/runner/subject.rb
@@ -68,7 +68,7 @@ module Mutant
       # @api private
       #
       def run
-        @mutations = subject.mutations.map do |mutation|
+        @mutations = subject.map do |mutation|
           Mutation.run(config, mutation)
         end
       end
diff --git a/spec/unit/mutant/runner/subject/mutations_spec.rb b/spec/unit/mutant/runner/subject/mutations_spec.rb
deleted file mode 100644
index d46b857f..00000000
--- a/spec/unit/mutant/runner/subject/mutations_spec.rb
+++ /dev/null
@@ -1,24 +0,0 @@
-require 'spec_helper'
-
-describe Mutant::Runner::Subject, '#mutations' do
-  let(:object) { described_class.run(config, mutation_subject) }
-
-  subject { object.mutations }
-
-  let(:config)           { mock('Config')                            }
-  let(:mutation)         { mock('Mutation')                          }
-  let(:mutation_subject) { mock('Subject', :mutations => [mutation]) }
-
-  class DummyRunner
-    include Concord.new(:config, :mutation)
-    def self.run(*args); new(*args); end
-  end
-
-  before do
-    stub_const('Mutant::Runner::Mutation', DummyRunner)
-  end
-
-  it { should eql([DummyRunner.new(config, mutation)]) }
-
-  it_should_behave_like 'an idempotent method'
-end
diff --git a/spec/unit/mutant/runner/subject/success_predicate_spec.rb b/spec/unit/mutant/runner/subject/success_predicate_spec.rb
index 05e14a4e..916a1ded 100644
--- a/spec/unit/mutant/runner/subject/success_predicate_spec.rb
+++ b/spec/unit/mutant/runner/subject/success_predicate_spec.rb
@@ -5,11 +5,11 @@ describe Mutant::Runner::Subject, '#success?' do
 
   let(:object) { described_class.run(config, mutation_subject) }
 
-  let(:mutation_subject) { mock('Subject', :mutations => mutations) }
-  let(:config)           { mock('Config')                           }
-  let(:mutation_a)       { mock('Mutation A', :fails? => false)     }
-  let(:mutation_b)       { mock('Mutation B', :fails? => false)     }
-  let(:mutations)        { [mutation_a, mutation_b]                 }
+  let(:mutation_subject) { mock('Subject', :map => mutations)    }
+  let(:config)           { mock('Config')                        }
+  let(:mutation_a)       { mock('Mutation A', :failed? => false) }
+  let(:mutation_b)       { mock('Mutation B', :failed? => false) }
+  let(:mutations)        { [mutation_a, mutation_b]              }
 
   class DummyMutationRunner
     include Concord.new(:config, :mutation)
@@ -19,7 +19,7 @@ describe Mutant::Runner::Subject, '#success?' do
     end
 
     def failed?
-      @mutation.fails?
+      @mutation.failed?
     end
   end
 
@@ -36,7 +36,7 @@ describe Mutant::Runner::Subject, '#success?' do
 
   context 'with failing evil mutations' do
     before do
-      mutation_a.stub(:fails? => true)
+      mutation_a.stub(:failed? => true)
     end
 
     it { should be(false) }